Refrigeration



July 16! l A. C. SMITH REFRIGERATION Original Filed Nov. 1, 1935 3 Sheets-S et 1 MIMI".

INVENTOR.

.19 9M RNEY.

July 16, 1940- A. c. SMITH REFRIGERATION ori inal Filed Nov. 1, 1935 5 Sheets-Sheet 2 v INVENTOR.

.06 ,Am ATTORNEY.

July 16, 1940. 2,207,701

A. c. SMITH REFRIGERATION Original Filed Nov. 1. 1935 3 Sheets-Sheet 3 Q AQATTORNEY.

INVENTOR.

Patented July 16, 1940 1 UNITED STATES PATENT OFFICE REFRIGERATION Delaware Application November 1, 1935, Serial No. 47,783 Renewed February 12, 1937 8 Claims.

, My invention relates to refrigeration, and more particularly to control mechanism for refrigeration apparatus of the continuous absorption type.

The object of my invention is to provide an improved control mechanism for initiating at will the defrosting of a refrigerator of the continuous absorption type, the control mechanism being operative to terminate the defrosting automatically.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims forming a part of this specification.

For a betterunderstanding of my invention reference may be had to the following description taken in connection with the accompanying drawings in which Fig. 1 is a front elevation, partly broken away, ofa refrigerator embodying my invention; Fig. 2 is a side elevation, partly broken away and in section,.of the refrigerator shown in Fig, 1; Fig. 3 is a view taken at line 3-3 of Fig. 1, and illustrates section control mechanism shown in connection with the refrigerator illustrated in Figs. 1 and 2,; Fig. 4 is a view, in section, taken at line 44 ofFig. 3; and Fig. 5 is a fragmentary view, in section, of a part of the control mechanism shownin Fig. 3.

Referring to Figs. 1 and 2 of the drawings, I have shownmy invention in connection with an absorption refrigerator of the pressure equalized continuous type. This refrigerator comprises a cooling element or evaporator l0 disposed in a heat insulated chamber II which may form 'a food storage compartment in the upper portion of a cabinet I2 and into which access may be had by a door l3. The refrigerant fluid, such as ammonia, evaporates in the evaporator l0 and diffuses into an inert pressure equalizing gas, such as hydrogen. The resulting gaseous mixture of refrigerant and hydrogen flows from the evaporator IU to an absorber (not shown) in which 4 the refrigerant gas is absorbed by a suitable liquid absorbent, such as water. The inert hydrogen gas is returned to the evaporator I0, and the enriched absorption liquid is conducted to a generator |4 disposed in a lower apparatus compartment l5. By heating the generator H the refrigerant is expelled from the absorption liquid, condensed in a suitable condenser, and then returned to the evaporator ID to complete the refrigerating cycle. The weakened absorption liquid from which the refrigerant has been expelled is conducted from the generator I 4 to the absorber to absorb refrigerant gas.

At the back of the cabinet |2 a passage It extends upwardly from the lower compartment l5 and in the rear of the chamber II, and the 5 absorber, condenser, and other parts of the machine may be disposed in the lower compartment l5 and this vertical passage l6. In order to simplify the drawings the last-mentioned parts have not been shown, their illustration not being necessary for an understanding of my invention.

The generator I4 is provided with a heating flue I1 and is adapted to be heated by a gas burner l8 arranged so that the flame 9 produced thereby is directed into the lower end of 15 the flue, and a suitable combustible gas is supplied through a conduit 20 and gas filter 2| to the burner l8.

In accordance with my invention the flow of gas to the burner I8 is controlled by control mechanism 22 interposed between the burner l8 and filter 2|. Referring to Fig. 4, the control mechanism 22 comprises a casing 23 having apertured bosses 24 and 25 which form inlet and outlet openings, respectively, for the combustible 25 gas. The gas flows from the inlet opening at the boss 24 through a passage 26 into a valve chamber 21, which is shown in Fig. 3. From the valve chamber 21 the gas passes into a diaphragm chamber 28 through a passage 29 formed in a bushing 30 which is threadedly secured at the open end of the chamber 21. The gas then passes from the diaphragm chamber 28 through a passage 3| to the outlet opening at the boss 25.

In this embodiment of my invention the righthand side of the bushing 30 forms a valve seat which is adapted to cooperate with a valve 32 having a triangular-shaped stem 33. The stem 33 extends through the passage 3| into the diaphragm chamber 28 and is provided at its end or biased toward its closed or seated position on the bushing 30 by a helical spring 35 disposed within the valve chamber 21. Means, hereinafter to be described, urges the valve 32 to an open position against the tension of the spring 35 to permit gas to flow from the valve chamber 21 through the passage 3| into the diaphragm chamber 28.

The diaphragm chamber 28 is enclosed by a flexible diaphragm 36 having the peripheral edge thereof secured between the open end of the casing 23 and a cover plate 31, a gasket 38 being provided to make the diaphragm chamber 28 gas-tight so that the flow of gas from this chamber to the outlet opening at the boss 25 is insured. To the central portion of the diaphragm 36 is secured a hub member 39 having an opening 46 extending therethrough, and to the hub member is fixed one face of an expansible bellows or hollow diaphragm 4|. A second hub member 42 provided with an opening 43 is fixed to the opposite face of the expansible bellows 4|, and to this hub member is secured a concave-shaped annular shell 44 having a flange or rim 45. A disk or diaphragm 46 is adapted to be disposed at the open end of the shell 44 with its flange or edge portion 4'! anchored and fitting tightly within the flange 45 and secured thereto in any suitable manner, as by welding or brazing.

The area of the diaphragm 46 is greater than the area of the open end of the shell 44, and is preferably formed of suitable material so that it is resilient and can be snapped between the positions shown in solid and dotted lines, respectively, in Fig. 3. When the diaphragm 46 is bowed outward, as shown in solid lines, and a force is exerted thereon toward the left, the diaphragm 46 will snap inward after passing the dead center position and assume the position shown in dotted lines, the extent to which the diaphragm moves being limited only by the extent to which it is capable of flexing. Conversely, when the diaphragm 46 is bowed inward and a force is exerted thereon toward the right, the diaphragm will snap outward after passing the dead center position and assume the out wardly bowed position, the extent to which the diaphragm moves outwardly being limited only by the extent to which it is capable of flexing. This snap action of the resilient diaphragm 46 is utilized to alter or modify the control of the valve 32, as will be described hereinafter.

It will be noted that the shell '44 sealed by the diaphragm 46, the opening 43 in the hub member 42, the expansible bellows 4|, and open-,

ing 46 in the hub member 39 form a completely enclosed space. To the opening 46 of the hub member 39 is secured one end of a capillary tube 48, the opposite end of which is secured 'to a thermal bulb 49 positioned in thermal contactwith the evaporator or cooling element l6, as: 5 shown in Fig. 2. The expansible bellows 4|,

capillary tube 48, and thermal bulb 49v constitute what is termed an expansible fluid thermostat which is filled with a suitable fluid that expands with an increase in temperature and becomes reduced in volume with a decrease in temper-f ature. The shell 44 and cooperating diaphragm 46 form a hollow member which is in commu,

nication with the expansible fluid thermostat by means of passage 43 in hub member 42.

During normal operation of the machine the diaphragm member 46 is bowed outwardly and adapted to cooperate with the enlarged head 34 of the valve 32 to control the flow of gas to the burner l8. Thus, when the temperature 'of the evaporator |6 increases the expansion of the fluid within the bellows 4| will cause the latter.

member 39 when the control mechanism is adjusted to its desired position, as will be hereinafter described, the portion thereof adjacent to the connection at the opening 46 of the hub member 39 is spiral-shaped, as shown in Fig. 3.

To adjust the expansible bellows 4| at any desired position to fix the position of the diaphragm 46 with respect to the head 34 of the valve 32, the cover plate 31 is provided with a central opening to receive a bushing 56 which is threadedly engaged to a sleeve 5|. A pin 52 extends through the sleeve 5| and is provided with a threaded outer portion to receive a clamping nut 53 for drawing the inner flanged end 54 of the pin against the inner end of the sleeve and also secure a cap 55 over the outer ends of the pin 52 and sleeve 5|.

A grooved pulley 56 is positioned over the cap 55 and secured thereto, as by a set-screw 51, and by rotating this pulley the pin 52 can be moved toward or away from the hub member 39 because of the threaded engagement of the sleeve 5| with the bushing 56. The inner end of the pin 52 is provided with a central protuberance 58 which is adapted to bear against or abut the end of the hub member 39. It will thus be seen that by rotating the pulley 56 to move the protuberance 58 toward the right it is operative to move the diaphragm 36 and expansible bellows 4| carried thereby toward the valve 32 and fix the diaphragm 46 at the desired position. with respect to the head 34 of the valve 32. It will be noted that the diaphragm 36 is normally bowed or. biased toward the cover plate 3| so that,'when the protuberance 58 is moved toward the left, the flexible diaphragm 36 will of its own accord follow the protuberance until it is adjusted to its desired position to fix the position of the resilient diaphragm 46 with respect to the valve 32.

Although the temperature of the cooling element |6 may be controlled at the lower compartment |5 by providing a dial and employing a suitable control knob in place of the grooved pulley 56, it is preferred to employ the latter and provideQsuitable operating mechanism for controlling the machine at the upper compartment As shown in Figs. 1 and 2, an indicating 'is similar to the grooved pulley 56 and operatively connected therewith by a flexible wire belt 63 having a guide-tube 64. It will thus be seen that when the knob 66 at the .frontof the cooling element I6 is turned the rod 6| and grooved pulley 62 secured thereto are caused to rotate and effect, through the wire belt 64, rotation of the grooved pulley 56 associated with the control j mechanism 22.

The control mechanism 22 is so constructed that only a half turn of the adjustment knob 66 is required to obtain full range adjustment of the thermostat for normal operation of the machine. To this end the hub member 39 is provided with a spiral cam 65 which extends about half-way or 180 around the periphery thereof, as shown most clearly in Fig. .5. Referring to Fig. 3, it will be noted that the inner end of the pin 52 is provided with a short radial arm 66 which is so positioned that it is adapted to ride on the cam 65 only when the pin 52 is moved more than a half-turn or 180. A movement of more than a half-turn is imparted to the pin 52 when Lil the] adjustment knob 60 is turned a like amount which, as shown in Fig. 1, will place the knob 60 in the position indicated at Defrost on the indicating scale 59. When such a movement of more than a half-turn is imparted to the pin 52 the radial arm 66 rides on thecam 65 and causes the hub member 39 and flexible diaphragm 36 and parts carried thereby to move an abnormal distance toward the valve 32. During this movement, the resilient diaphragm 46 contacts the head 34 which is stopped by the bushing 30, and thus exerts a force on the dia-,

phragm 46 which causes the latter to snap from its normally outwardly bowed position to an inwardly bowed position, as shown in dotted lines in Fig. 3. The adjustment knob 60 is then returned to a position at the lower half of the dial 59, and in so turning the knob 66 the radial arm 66 is disengaged from the cam 65.

With the resilient diaphragm 46 now in an inwardly bowed position, it will not be effective to open the valve 32 with a normal increase of the temperature of the cooling element l0. As the temperature of the cooling element 16 increases, the bellows 4| expands and moves the diaphragm 46 toward the head 34 of the valve 32. When the cooling element In reaches an abnormally high temperature, which temperature is preferably above the freezing temperature of water, the pressure of the fluid within the shell 44 is sufficiently great to force the diaphragm 46 to its outwardly bowed position so as to contact the head 34 and open the valve 32.

During the period of time the diaphragm 46 is bowed inwardly and does not positively control the valve 32 the supply of gasto the burner I8 is reduced, thereby decreasing the heating of the generator 14 and permitting the temperature of the cooling element H) to increase. When the temperature of the cooling element In increases to a value above the freezing temperature of water, frost that may have accumulated on the cooling element Ill will melt and can be collected in a suitable receptacle (not shown). The control mechanism is preferably adjusted so that, when the adjusting knob 66 is moved to initiate defrosting of the cooling element ID, the latter will remain at a temperature above the freezing temperature of water sufiiciently long to insure substantially complete melting of frost which has accumulated on the cooling element I6.

When the diaphragm 46 is snapped to its outwardly bowed position, as described above, the valve 32 is immediately moved to an open position to permit heatingef thegenerator l5 so that the temperature of the cooling element III will decrease to a value in the normal operating range of the machine. This normal value of temperature is determined, of course, by the position of the adjustment knob 60 at the lower half of the dial to which it has been returned after being moved momentarily to the upper half of the dial to initiate defrosting.

After the cooling element l0 reaches'the normal temperature at which it is adjusted to oper ate, the control mechanism, with the diaphragm 46 in its outwardly bowed position, will be operative to control the valve 32 in response to temperature changes of the cooling element [6 to maintain the latter at a substantially constant temperature. When frost has again accumulated on the cooling element ID to such an extent that defrosting is desired, the adjustment knob 60 is moved to the portion of the dial indicated Deperature condition.

frost and then returned to the lower half of the dial to a position at which it is desired that normal operation will resume after the defrosting has automatically terminated.

Although I have shown my improved control mechanism in connection with a particular type of refrigerator, I do not wish to be limited to the particular arrangement set forth, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of my invention.

What is claimed is:

1. Refrigeration apparatus including a thermostat operative responsive to a temperature condition affected by said apparatus and having a movable part, structure associating said movable part and said control device in a normal operative relation and including a flexible member anchored at opposite edge portions and flexed to a first position, means for flexing said flexible member to a second position to alter said normal operative relation, and means whereby said flexible member returns to said first position from said second position responsive to abnormal change in said temperature condition to restore said normal operative relation.

2. Refrigeration apparatus including a thermostat element operative responsive to a temperature condition affected by said apparatus, a device for controlling operation of said apparatus,

' a hollow member having a flexible snap-acting diaphragm anchored at its edge portions, and structure including said hollow member to provide a connection between said thermostat element and said control device so that the operative relation between said thermostat element and said control device is changed responsive to internal pressure on said diaphragm.

3. Refrigeration apparatus including an ex-. pansible fluid thermostat operative responsive to a temperature condition affected by said apparatus and having a movable part, a device for controlling operation of said apparatus, and structure for operatively associating said movable part and said control device and including a. hollow member having a snap-action wall, the interior of said hollow member communicating with said expansible fluid thermostat to cause outward snapping of said wall to change the operative relation between said'movable part and said control device responsive to pressure in said thermostat.

- 4. Refrigeration apparatus including a thermostat operative responsive to a temperature condition affected by said apparatus and having a movable part, structure adapted to connect said movable part and said control device and including a hollow member having a snap-action wall, said hollow member containing an expansible fluid affected by said temperature condition so as to cause outward snapping of said wall to change the operative relation-between said movable part and said control device upon increase in said tem- 5. Refrigeration apparatus including a cooling element, a device for controlling operation of said apparatus, a thermostat element operative responsive to a temperature condition affected by said cooling element, structure to provide a connection between said thermostat element and said control device and including a snap-acting flexible member anchored at opposite edge portions, means for snapping said flexible member in one direction to shorten the connection between said thermostat element and said control device, and

means responsive to change in said temperature condition for snapping said flexible member in the opposite direction to lengthen the connection between said thermostat element and said control device.

6. Refrigeration apparatus including a thermal element operative responsive to a temperature condition afiected by said apparatus, a control member for controlling operation of said apparatus, structure associating said thermal element and said control member in a normal operative relation and including a, flexible member anchored at opposite edge portions and flexed to a first position, means to bodily move said thermal element to cause said flexible member to flex to a second position to alter said normal operative relation, and means to return said flexible member to said first position to restore said normal operative relation.

'7. Refrigeration apparatus including a thermostat element responsive to a temperature condition afiected by said apparatus, a flexible member anchored at opposite edge portions and movable back and forth from a normally bowed position at one side of dead-center to a second bowed position at the opposite side of dead-center, structure associating said thermostat element and said control member in a normal operative relation and including said flexible member in said normally bowed position, and means for snapping said flexible member from its normally bowed position to said second position at the opposite side of dead-center to alter the normal operative relation of said thermostat element and said control member.

8. Refrigeration apparatus including a regulator operative responsive to a condition afiected by said apparatus and including a movable part, a control member for controlling operation of said apparatus, structure associating said movable part and said control member whereby said regulator is capable of operating said control member, said structure including a flexible member limited in movement only by the extent to which it is capable of flexing and being so constructed and arranged that said movable part and said control member are associated in a normal operative relation when said flexible member is in a first position, means for flexing said flexible member to a second position to alter said normal operative relation, and means whereby said flexible member returns to said first position from said second position with rise of temperature to restore said normal operative relation.

ALBERT C. SMITH. 

